It is proposed to develop a pulsed hydrogen fluoride (HF) chemical laser system that is specifically designed for use in corneal microsurgery. Laser parameters such as pulse energy, pulse duration, beam quality, and output spectra will be optimized for application in corneal microsurgery. Issues related to use in a medical environment (such as laser size and packaging, fuels and exhaust handling, EMI suppression, and fiber optic delivery of laser radiation) will be addressed. The specific aims and objectives of the proposed research are: 1) to determine optical properties and optimal ablation parameters for efficient microsurgical removal of corneal tissue, 2) to determine spatial and temporal resolution and control requirements for optimal tissue removal, 3) to evaluate adjacent tissue damage by histological examination of post-irradiated tissues, 4) to develop a prototype HF chemical laser system with refined laser parameters for corneal microsurgery, and 5) to consider catheter delivery of laser radiation by means of an optical fiber system. The methodology of Phase I work will include modification of a Helios Model PCLI pulsed HF chemical laser to provide variation of laser parameters, microscale laser/tissue interactions experiments, and pre- and post-irradiation characterization of tissue samples. If successful, the program will be continued in Phase II and Phase III SBIR work to develop a new clinical instrument that permits refined corneal microsurgery using safe and effective infrared laser irradiation.